Violations of body cavities may occur for any of a number of reasons such as surgery, wounds or, in the case of pleural space invasion, rupture caused by coughing or disease. As a consequence atmospheric air, body gases and other fluids may invade the cavities and, e.g., in the case of pleurae, fill the pleural spaces thereby decreasing the lung capacity. If sufficient fluids accumulate the intimate contact between pleura and lung would be broken thereby preventing the outward pull of the pleura on the lung which results in shrinkage of the lung, i.e., a "collapsed" lung.
Another possible deleterious consequence of such a pleural space invasion would be a mediastinal shift in which the mediastinum, or space between the lungs, which contains such organs as the heart, is displaced from the center thereby compressing said organs. This could result in blood circulation problems and heart cessation.
Thus, it is desirable to remove such invasive fluids from the body cavities as quickly and completely as possible.
Furthermore, blood lost as a result of the above factors must be replaced either by the patient's own blood, i.e., auto-transfusion, or donated blood.
Due to the current atmosphere of fear with respect to AIDS, hepatitis and the like, transfusions of donated blood are becoming more difficult to effect.
Therefore, the demand for autotransfusion of the patient's own blood is growing with a concomitantly increasing need to recover blood lost by the patient due to the factors listed above.
However, to date, the recovery of such blood has been complicated and expensive.
In U.S. Pat. No. 4,540,413 there is described a drainage unit with "blood transfer adapter" which allegedly obviates the above problems. The Patented system depends upon the presence of a liquid seal in the drainage chamber, at the time of connection of the unit to the patient to prevent entry of atmospheric air to the body cavity. Thus, the device must comprise a liquid seal before any drainage of fluids in order to prevent possible pneumothorax before drainage would by sufficient to effect such a seal in the absence of added liquids. Such a system suffers from the major drawbacks of many of the earlier drainage units, that is that an instantaneous decrease of the pressure in the body cavity, e.g., due to gasping respiration of the patient, could result in aspiration of the fluids from the drainage chamber back into the body cavity or the mounting level of fluid in the chamber might impose a progressively increasing resistance to drainage thereby requiring progressively decreased vacuum pressures with its concomitant added monitoring requirements. Furthermore, the advantage of having anti-clotting agents present in the liquid seal (i.e. drainage) chamber would be negated by the fact that as fluid is removed from the drainage chamber some of said agents would also be removed thereby decreasing their concentrations in the drainage sump.
In addition, any debris present in the draining fluid might tend to build up in or around the drainage tube thereby partially or completely clogging it. This might result in slower, or complete cessation of, drainage with the concomitant deleterious effects of poor drainage and/or excess pressure buildup in the body cavity.
Thus, the blood could not "be readily transferred to . . . an autotransfusion device" as the blood is not "processed", as indicated therein, but would require additional processing for removal of said debris, etc. as well as the added anti-coagulants. (Emphasis added)
In addition the blood might be foamed as a result of the bubbles passing therethough which would prevent its immediate use for reinfusion. Said bubbling might also cause damage to the blood components.
Other prior art drainage systems are described in my co-pending application Ser. No. 801,205, filed Nov. 25, 1985, which is incorporated herein by reference. The drainage systems, described therein, which obviate the above problems by removing the liquid (water) seal from the drainage chamber to the other, e.g., suction control, chambers suffer from the disadvantage of being cumbersome. Furthermore, their use is position dependent in that any changes in height of the liquid, e.g., as a result of tilting in the suction and/or water seal chambers of, e.g., the Deknatel(.TM.) Pleur-evac(.TM.) drainage systems (Deknatel division of Howmedica, Inc., Floral Park, N.Y.) will effect changes in the suction applied to the patient. In addition, changes in water level as a result of evaporation or entrainment in the evacuated gases will also affect accurate control of pressures within the system. To overcome those problems constant monitoring of, or periodic additions of water to maintain the liquid levels of the water seal containing chambers is required with their concomitant potential for operator errors.
The drainage system described in said co-pending application Ser. No. 801,205 avoids those problems by removing all liquid seals and uses purely mechanical means, such as flapper valves on the drainage inlet tube and excess positive or negative pressure relief valves. Therefore, although liquids may be present in the chamber after drainage has been initiated the applied suction cannot be affected by changes in the liquid level therein and the patient is protected from pnemothorax upon attachment to the device. Furthermore, said invention also avoids the cumbersome aspects of the prior art devices by providing a single easily detachable drainage collection chamber to which is removably and sealably affixed a cap comprising all of the controls, valves and inlet and outlet ports from which the collection chamber could be removed without disconnecting the drainage unit from the patient.
The Pleur-evac(.TM.) ATS, an autotransfusion system based upon the above described Deknatel drainage system, with its concomitant disadvantages, interposes, for autotransfusion purposes, an autotransfusion bag between the patient and the drainage chamber. The autotransfusion bag is flexible but has a rigid top which comprises inlet and outlet stems. Thus, there is always some air present in the bag which contributes to the deterioration of the drained blood exposed thereto and opposes the draining fluids. Furthermore, in order to maintain the autotransfusion bag in an open condition while under vacuum a support frame must be attached to said bag during filling. The bag must then be removed from the frame before being used for reinsfusion.
Furthermore, when changing or removal of the bag is required the drainage unit must be disconnected from the patient. This may have undesirable effects if it occurs at an inconvenient time during the drainage process.
Another autotransfusion system, described by Sorensen, comprises a collapsible collection bag which also suffers from the disadvantage of incomplete evacuation due to the top thereof being flat. Furthermore, in order to prevent collapse of the bag, due to the applied suction, which would preclude entry of the drained fluids therein the bag must be placed in another receptacle to which suction is applied and collapse of the bag prevent. Such a system is cumbersome and complex of operation.
The present invention overcomes said disadvantages by providing a compact continuous drainage system which purifies and collects the drainage fluids, prior to the passage thereof into the autotransfusion bag, which does not require a frame to allow filling said bag, and does not require disconnecting of the drainage system from the patient or cessation of suction and/or drainage during the filling and/or removal of the autotransfusion bag.